Artificial intelligence books for a counter? They lack natural warmth (8)
I believe the answer is:
reptilia
'they lack natural warmth' is the definition.
The definition suggests an adverb but the answer is not.
'artificial intelligence books for a counter?' is the wordplay.
'artificial intelligence' becomes 'ai' ('AI' can be a synonym of 'artificial intelligence').
'books' becomes 'lit' (abbreviation for literature).
'for' is a charade indicator (letters next to each other).
'a' becomes 'per'.
'counter?' shows that the letters should be reversed in order (I've seen 'counter' mean this).
'ai'+'lit'+'per'='ailitper'
'ailitper' backwards is 'REPTILIA'.
Can you help me to learn more?
(Other definitions for reptilia that I've seen before include "Class including lizards" , "Class of cold-blooded animals" .)